Current mail handling processes utilized by the United State Postal Service and others rely on mail trays and tubs to hold and transport mail pieces during mail collection, sorting and distribution. For example, unsorted collected mail is often transported in mail tubs and sorted mail may be loaded into the tubs for carrier delivery. Due to the automated nature of current mail processing systems, these containers are routinely transported on conveyors to and from different locations and machines during mail processing operations. In some cases, it is necessary to accumulate empty containers on a conveyor, divert containers on or off the conveyor and/or load the containers while the containers are positioned on the conveyor. When accumulating containers on a conveyor, it may be necessary to stop one or more of the containers while continuing to run the conveyor in order to advance other containers on the conveyor.
Prior art devices used to stop and/or hold a container in position on a moving conveyor tend to be large mechanisms and/or include numerous moving parts. In the case of roller-type conveyors prior art designs included a pop-up roller that is raised into the path of oncoming objects on the conveyor. Other conveyor stop devices include pop-up mechanisms actuated with a solenoid or air cylinder. However, the useful lifetime of components such as solenoids and air cylinders is limited due to wear of seals, cylinders and other moving parts.